1. Field of the Invention
The instant disclosure relates to an insulting encapsulation structure, and more particularly to an insulating encapsulation structure for a chip type solid electrolytic capacitor.
2. Description of Related Art
With the development of mini electronics and high-density printed circuit boards with high efficiency, the development of a chip type solid electrolytic capacitor has been increasing rapidly. A commercially available solid electrolytic capacitor mainly employs metals such as aluminum, tantalum, niobium, or titanium. Among those, aluminum and tantalum are the most widely used in the production of solid electrolytic capacitors.
In the manufacturing of aluminum solid electrolytic capacitors, an aluminum foil is subject to an electrolytic etching process to form a thin metal core structure 1, as shown in FIG. 1. The Oxide layers 11 and 12, which possess on the surface thereof, are then respectively formed on the top and bottom surfaces of the center conducting layer 1. Next, the sandwich structure is cut into aluminum body 13 of predetermined shapes by a cutting or a punching method, as shown in FIG. 2. When the aluminum body (the sandwich structure) 13 is undergone the cut/punching process, part of the aluminum core layer 14 is exposed from the edges. A highly conductive polymeric layer is then disposed on the sandwich structure 13. Conventionally, to prevent the electrically conductive polymeric layer from contacting the exposed aluminum core layer 14 and causing short circuit, a second oxidation process is taken place to provide additional oxide layers over the aluminum core layer 14 before a carbon or silver glue can be subsequently applied over the aluminum body 13.
However, the cutting/punching process often causes the edges of the metallic body 13 to crack and deform, thus leaving imperfect burrs around the edges. The burrs on the aluminum body 13 may hinder the proper adherence of the oxide layer onto the aluminum body 13. As a result, increased current leakage problems may occur in the formation of the capacitor.
Therefore, there is a need of an insulating encapsulation structure for a solid chip electrolytic capacitor which overcomes the above disadvantages.